Spinal discs between the endplates of adjacent vertebrae in a spinal column of the human body provide critical support between the adjacent vertebrae. These discs can rupture, degenerate and/or protrude due to injury, degradation, disease or the like to such a degree that the intervertebral space between adjacent vertebrae collapses as the disc loses at least a part of its support function. This can cause impingement of the nerve roots and severe pain. In some cases, surgical correction may be required.
Typically, the surgical correction includes the removal of the natural spinal disc from between the adjacent vertebrae and, in order to preserve the intervertebral disc space for proper spinal-column function, a motion and alignment preserving prosthetic device can be inserted in the intervertebral space between the adjacent vertebrae. In this context, the motion and alignment preserving prosthetic device may be referred to as a motion preservation disc.
In some cases, the inserted motion preservation disc may not function properly for any of a wide variety of reasons including, for example, failure of or damage to the artificial disc, poor tissue healing, the deterioration of the function and/or shape of the spinal column after the surgical correction, end plate or implant subsidence, pain, and/or other patient-related factors. In response, revision surgery, that is, another surgical correction may be required in which the motion preservation disc is removed from the intervertebral space between the adjacent vertebrae. After removal of the disc, a replacement implant, typically a fusion-type implant, may be introduced to the intervertebral space.
Removal of an existing motion preservation disc can be traumatic and painful for a patient. For example, it may require portions of bone to be re-sected, which in some cases may impair the structural integrity of the joint. In other cases, removal may disturb the alignment required for proper fusion.
Although there continue to be improvements made to motion preservation disc implants and to revision techniques, a need remains for a device that can restrict the motion of previously implanted motion preservation discs while limiting patient trauma.